SwiftUI can be ridiculously fast – closer to a 3D framework than a typical 2D windowing framework – because it can reduce to a set of uninterrupted draw calls.

SwiftUI can be ridiculously fast – closer to a 3D framework than a typical 2D windowing framework – because it can reduce to a set of uninterrupted draw calls. Rendering is not why SwiftUI can be slow. If you don't know what you're doing, it's possible for SwiftUI to think your new view is unrelated to the old view and everything needs deallocation and reallocation.